U.S. Pat. No. 5,426,545 describes a disturbance compensation system for compensating disturbances which may occur when a disk drive is operated. The disturbing event is, for example, a shock or a vibration. The system measures the disturbance created by the acceleration of the disk and then supplies a correction signal which, after being filtered, is used for compensating the effects of the shock or the vibration. The system makes use of an angular acceleration sensor. The method works continuously, that is to say, that the accelerometer operates permanently while the correction signal is calculated without interruption.
An accelerometer is a sophisticated component and thus costly. Its use makes particular arrangements necessary of the servo control system.